Attachment for pulleys



I. A. BURNETT.

ATTACHMENT FOR PULLEYS.

APPLICATION FILED JUNE 7. 1920.

1,376,742. Patented May3, 1921.

z gvz. v 2

Inn/en to r 11126728 5 I GAZ ii/eLA M/ I ga z/sw (w M IRA A. BURNETT, OFCHICAGO, ILLINOIS.

ATTACHMENT 1'03 PULIIEYS.

Specification of Letters Patent.

Patented May 3, 1921.

Application filed June 7, 1920. Serial llo. 387,112.

To all whom it may conoem:

Be it known that I, IRA A. BURNn'rr, a citizen of the United States,residin at Chicago, in the county of Cook and tate of Illinois, haveinvented certain new and useful Im rovements in Attachments for Pulleys,0 which the following is a specification.

This invention relates to pulleys in general, but has particularrelation to that class of pulleys used in connection with dentalengines, and which are provided with peripheral or annular grooves forthe reception and operation of belts, usually in the form of cords orcables, employed for the transmission of power.

While the invention is more particularly intended for use in connectionwith grooved pulleys employed on dental engines, and it is so shown inthe drawing forming a part of this specification and will be hereinafterso described, yet it will be obvious that it is applicable for use onpulleys without grooves in their peripheries on belt engaging surfaces,and for this reason I do not desire to be understood as limiting myselfin its applicability to any specific type of pul- Ihe invention consistsin certain peculiarities of the construction, novel arrangement andoperation of the various parts thereof, as will be hereinafter morefully set forth and specifically claimed.

As is well known to dentists, as well as to others skilled in the art towhich the invention pertains, grooved pulleys of the constructionheretofore in general use become worn at the bases of their grooves bythe operation of the belts used in connection therewith, to such anextent that the belts slip or fail to transmit power properly, andbesides require frequent adjustment in their lengths, or hitches to betaken therein to accommodate for the wear of the hubs or cores of thepulleys.

After considerable use, the pulleys become so badly worn at their beltengaging surfaces that they have to be discarded and replaced by newones. As the pulleys used on dental engines are made of high gradematerial and by skilled workmen, they are of course, costly, and toavoid frequent purchase of new ones, by furnishing a simple andinexpensive attachment of such construction that it can be readilyplaced in operative position on a pulley or easily respondin movedtherefrom, to the end, that when its belt enga ng surface shall havebecome worn or eficlent, it can be removed and replaced by a new andmore eflicient attachment, is one of the objects of the invention.

Another object of the invention is to rovide an attachment for pulleyswhich s all be made of resilient material, to the end, that it can beeasily placed on and removed from a pulley and which will provide a beltengaging surface of such character that the belt will have a better ripthereon and slipping of the same wil be practically eliminated.

Other objects and advantages of the inventlon Wlll be set forth in thefollowing descrlption and explanation.

' In the accompanying drawing- Figure 1 is a face view of a pulleyequipped with an attachment embodying my invention.

Fig. 2 is a central sectional view taken on line 2-2 of Fig. 1 lookingin the direction indicated by the arrows.

Fig. 3' is a plan or side view .of a pulley without the attachment, and

Fig. 4 is a detached plan view of the attachment. v v

Like numerals of reference refer to correparts throughout the differentviews 0 the drawing.

Thev reference numeral 5 designates the hollow hub of a pulley which maybe mounted on a suitable shaft and rigidly secured thereto by means ofa. set -screw located in an opening 6 near one of the ends of the hub.As is clearly shown in Fig. 2 of the drawing the hub is provided with aplurality of peripheral flanges 7, 8 and 9 which are spaced apart andprovide annular grooves or guideways 10 which are ordinarlly employedfor the reception and guidance' of a belt used for transmitting powerfrom the pulley to another part.

In the present instance, I have shown the pulley as being of the doubletype, or as having two of the grooves 10' from one of which to the otherthe belt can be changed as desired, but it will be understood that oneof the flanges, for example, the flange indicated by the numeral 7, maybe omitted when it is apparent that a hub of the single groove type willbe provided. The flange 8 is by preference provided on its surfaceopposite the flange 9 with an annular shoulder 11 which is concentricwith the hub and the flange 8 but located some distance inwardly fromthe free edge of said flange.

In the drawing, I have shown the attachment embodying my invention asbeing constructed for application to'one pair of flanges and theresultant groove there-between only. The attachment consists of anannular member or ring made of rubber or any other suitable resilientmaterial and having on its inner periphery a pair of 1nwardly extendedflanges 12 and 13 and on its outer periphery a pair of annular flanges14 and 15. Between the flanges 12 and extended inwardly of the circularattachment is an annular rib 16 which is separated from the flanges 12and 13 by outwardly extended recesses 17 in which are located theflanges 8 and 9 of the pulley. The rib 16 is crosssectionally rounded atits inner portion to rest against the base of the groove 10. The flange12 of the attachment is of less width than the flange 13 which latterflange is adapted to rest at its inner or free edge against the shoulder11 on the outer surface of the flange 8 of the pulley. By thisarrangement it is apparent that as the attachment is made of resilientor elastic material, it can be readily placed in position on the pulleyby stretching the ring sufliciently to permit the rib 16 to be locatedbetween the flanges 8 and 9 of the pulley when by reason of theelasticity or resiliency of the attachment it will contract itself sothat the rib 16 will fit closely between the flanges 8 and 9 of thepulley and in such a manner that the inner surface of the rib 16 willrest firmly against the base of the groove 10 of the pulle lVhen in thisposition the recesses 17 o the circular attachment will receive and holdthe flanges 8 and 9 in such a way that the attachment will be securelyretained in position. The spaced flanges l1 and 15 of the attachmentprovide there-between an annular groove 18, the base of which terminatesat the outer surface of the rib 16 and thus a resilient belt engagingmember will be pro vided for the reception and operation of the beltused in connection with the pulley. As the attachment is made ofresilient material, it is obvious that the belt engaging surface orportion thereof will afford a better grip ping surface or track for thebelt than that provided by a metallic surface, and it is further evidentthat after the attachment becomes materially Worn or damaged, it can bequickly removed from the pulley and replaced by a new or perfectattachment at a very small expense.

lVhile I have shown the attachment provided with an inwardly extendedrib 16 on its inner periphery to fit within the groove 10 of the pulley,and will so construct it when used in connection with the groovedpulley, yet it will be understood that by omitting the inwardly extendedrib 16 located between the flanges 12 and 13 of the attachment, but byemploying said flanges, the attachment can be successfully applied to apulley having a cylindrical surface or one without the peripheral groovetherein, for it is manifest that the flanges 12 and 13 of the attachmentwill clamp the sides of the pulley and thus hold the attachment inposition thereon.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is- 1. An attachment for pulleys consistingof a relatively stifl annular resilient member having in its innerperiphery a pair of spaced annular grooves for the reception of theflanges of a pulley and on its outer periphery a pair of spaced annularflanges providing there-between an annular groove, for the reception andoperation of a belt.

2. An attachment for pulleys consisting of a relatively stiff annularresilient member having in its inner periphery a plurality of spacedannular grooves for the reception of flanges on a pulley and on itsouter periphery a plurality of spaced annular-flanges providing betweeneach pair of said outer flanges an annular groove.

3. An attachment for pulleys consisting of a relatively stiff annularresilient member having in its inner periphery a plurality of spacedannular grooves for the reception of spaced flanges on a pulley and onits outer periphery a plurality of spaced annular flanges providingbetween each pair of flanges an annular groove, an annular rib extendedinwardly between the grooves in the inner periphery of the member.

4. An attaclnnent for pulleys consisting of a relatively stiff annularresilient member having on its inner. periphery a pair of laterallyspaced flanges and between said flanges a pair of laterally spacedgrooves for the reception there-between of a pulley and its flanges andon its outer periphery a pair of spaced annular flanges providingthere-between an annular groove for the reception of a belt. an annularrib extended inwardly between the grooves in the inner periphery of themember, one of the flanges of said member being greater in diameter thanthe other flange thereof.

IRA A. BURNETT.

